The invention relates to a lamp housing, particularly a spotlight housing.
DE 198 16 364 C2 has disclosed a lamp housing, which is used for accommodating a luminous body, a transparent cover plate in the form of a protective plate or a lens plate and a reflector. Burners or lamps, preferably discharge lamps with a base at one end, with a vertical or horizontal installed position, i.e. in each case at right angles to the optical axis, or with an axial installed position, i.e. in the optical axis, are used as luminous bodies.
The lamps have a gas-filled glass body with electrodes arranged therein, a lamp base, through which the feed lines to the electrodes are passed, and two or more contact pins, which are arranged on that end of the lamp base which is opposite the glass body. The contact pins are inserted into the sockets of a lampholder connected to the lamp housing in order to connect the lamp to a voltage source, a tight fit between the sockets and the contact pins being necessary for the high current levels of the lamp current to be transmitted.
At the same time, the contact pins, for example of discharge lamps with a base at one end, are used as fastening means for the discharge lamp. Since, as lamp powers increase, also the physical size of the discharge lamps and in particular the physical length of the glass body and of the lamp base increase, the lamps in the case of relatively high lamp powers have such a physical size that, in particular in the case of a horizontal installed position of the discharge lamps, considerable forces are exerted on the contact pins which, in addition to supplying current, also act as fastening contacts.
These forces result in an impairment of the contact between the contact pins and the sockets of the lampholder, which is associated with increased transfer resistance when transmitting the lamp current, a displacement of the lamp from the focal point of the reflector and, as a result of this, a reduced luminous efficiency and with a transmission of the forces into the lamp interior, which may result in impermissible voltages and ultimately in failure of the lamp.
The disadvantages of mounting the lamp exclusively via the contact pins are not only noticeable in the steady-state range in terms of the physical size of the lamp, however, but in particular also in the dynamic range during transport of a spotlight or its operation with jerky pivoting movements, impacts on the lamp housing and the like.
In order to be able to use a lamp housing for lamps with different lamp base diameters without replacing an accommodating device and to be able to use the contact pins of the lamps exclusively for transmitting the lamp current, in the case of the lamp housing known from DE 198 16 364 C2 the accommodating device comprises clamping jaws, which engage around the lamp base and can be adjusted by means of the adjusting device into an opening position, in which the lamp base is released, and into a locking position, in which the lamp base is fixed. The adjusting device comprises a latch with two sloping faces, which are designed to be geometrically identical and bear against the upper and lower clamping jaw in such a way that, when the latch is adjusted, the clamping jaws are spread apart radially.